A typical roller cone earth boring bit, such as used to drill wells, has three cones that roll around a common axis. The cones are mounted to bearing pins that depend from head sections. A seal contains lubricant within the cavity of the cone surrounding the bearing pin. A compensator in communication with the lubricant equalizes the pressure of the lubricant with the drilling fluid hydrostatic pressure on the exterior of bit. The purpose of the seal is to prevent the entry of foreign debris from the exterior of the bit that can enter and damage the earth boring bit. The head sections are welded together to form a body that is threaded at the upper end for connection to a drill string.
One type of seal is disclosed in U.S. Pat. No. 6,142,249, to Zahradnik, for a rigid metal face bearing seal with a secondary seal to partially seal against debris from the exterior of the bit. Despite the improvements achieved with the secondary seal, a void is formed between the metal face seal rigid ring, the energizing elastomer ring, and the secondary seal. This void then has to be filled with an oil or lubricant.